Does anyone own or know of someone that owns a Frankford Arsenal AR15 ? I am desperately seeking info about a rifle that all I can find out is that it was made for FA back in the late 70's and early 80's by S.G.W. which now known as Olympic Arms. Any other info would be greatly appreciated. It does have the "A" stamped in the auto position so maybe at one time it was a registered machinegun that was converted back to semi-auto? That would make me a very happy camper indeed. (and maybe increase the value)?

you can stamp anything you want on the side of your receiver... doesn't make it a machine gun. As long as the sear hole isn't drilled it's a semi auto. The prior owner may have used a DIAS or autoconnector in it... or, maybe the manufacturer just sold them with the A stamped in place. I seem to remember some small name manufacturer selling receivers marked "M16" and "semi/auto" a few years back.... doesn't make it anything other than a semiauto receiver though...